Strawberry Poison-dart Frog
The strawberry poison frog or strawberry poison-dart frog, (Oophaga pumilio) is a species of poison dart frog found in Central America. It is common throughout its range, which extends from eastern central Nicaragua through Costa Rica and northwestern Panama. The species is often found in humid lowlands and premontane forest, but large populations are also found in disturbed areas such as plantations. The strawberry poison frog is perhaps most famous for its widespread variation in coloration, comprising approximately 15-30 color morphs, most of which are presumed to be true-breeding.
The strawberry poison frog is conspicuously colored, and has been shown to be aposematic. The bright, aposematic colors displayed by O. pumilio are used to warn predators that they are unprofitable prey. O. pumilio is highly toxic due to diet-derived steroidal alkaloid toxins which it sequesters in its skin . These alkaloids are highly toxic, affecting nerve and muscle activity . Due to their high toxicity, predators quickly learn to associate their bright coloration with unprofitability and consequently leave the frogs alone .
Distinguishing characteristics of this species include bright coloration, extensive female parental care, modified larval teeth, a longer finger II than finger I, and modified finger discs that look much like the toes of tree frogs (Grant et al., 2006). The most common color pattern throughout the species' range is a red body with the upper surfaces of the hind limbs blue, purple, or black. This morph is often described as "blue jeans" coloration pattern.
O. pumilio has a specialized diet of small arthropods, primarily formicine ants . The frogs, like most Poison dart frogs, are harmless when not fed on ants or beetles-this has resulted in pumilio becoming a rather popular exotic pet.
Oophaga pumilio is diurnal and primarily terrestrial, and can often be found in leaf litter in both forested and disturbed areas. Though brightly colored and toxic, these frogs are relatively small, growing to approximately 17.5-22mm in standard length . Males are extremely territorial, guarding small territories.
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Reproduction and parental care
Oophaga pumilio and other species of the genus Oophaga are notable in the amphibian world for exhibiting a high degree of parental care. The strawberry poison frog has dual parental care. The males defend and water the nests, and the females feed the oophagous tadpoles their unfertilized eggs. Although both sexes contribute to parental care, females invest more heavily in terms of energy expenditure, time investment, and loss of potential reproduction. Females provide energetically costly eggs to the tadpoles for 6–8 weeks (until metamorphosis), remain sexually inactive during tadpole rearing, and care for only one clutch of 4-6 tadpoles at a time. The males, on the other hand, contribute the relatively "cheap" (in terms of energy) act of watering and protecting the eggs for a relatively short period (10–12 days), remain sexually active during the period of tadpole rearing, and can care for multiple nests at one time . The extreme maternal investment in their offspring is believed to be the result of high egg mortality. Only 5-12% of the clutch develops into tadpoles, and so the female's fitness may be best increased by making sure that those few eggs that form tadpoles survive .
Unlike many frog species, amplexus is absent in O. pumilio, with mating individuals instead exhibiting a distinct vent-to-vent position in which the female lays eggs and the male fertilizes them. After mating, the female will lay an average of three to five eggs on a leaf or bromeliad axil. The male will then ensure that the eggs are kept hydrated by transporting water in his cloaca. After about ten days, the eggs hatch and the female transports the tadpoles on her back to some water-filled location. In captivity, on rare occasions the male is observed transporting the tadpoles, though whether this is intentional, or the tadpoles simply hitch a ride, is unknown. Bromeliad axils are frequently used tadpole deposition sites, but anything suitable can be used, such as knots in trees, small puddles, or human trash such as aluminum cans.
Tadpoles are deposited singly at each location. Once this has been done, the female will come to each tadpole every few days and deposit several unfertilized food eggs (Savage, 2002). In captivity, tadpoles have been raised on a variety of diets, ranging from algae to the eggs of other dart frogs, but with minimal success. O. pumilio tadpoles are considered obligate egg feeders, as they are unable to accept any other form of nutrition.
After about a month, the tadpole will metamorphose into a small froglet. Generally, they stay near their water source for a few days for protection as they absorb the rest of their tail.
Oophaga pumilio belongs to the genus Oophaga, although the name Dendrobates pumilio is still most commonly used. There is evidence that the species of the Oophaga genus (previously classified as the "female parental care group" of Dendrobates) are a monophyletic evolutionary group. Due to the low level of genetic divergence between the species analyzed in this genus, it is estimated that they speciated relatively recently, after the formation of the current Panamanian land bridge in the Pliocene (3-5 million years ago). Oophaga pumilio is believed to be most closely related to Oophaga arborea.
Oophaga pumilio is a popular frog in captivity, due to its striking colors and unique life cycle. They have been imported in vast quantities to the United States and Europe since the early 1990s, when they would typically be available for around US$30 each. However, these shipments have since stopped, and O. pumilio is much less common and available in reduced diversity. In Europe, O. pumilio is much more diverse and available due to an increased frequency of smuggling and the resulting offspring of smuggled animals. Smuggling of dart frogs is less common elsewhere, but still problematic as it kills large numbers of animals and frequently degrades or destroys viable habitat.
Recently, O. pumilio has been exported from Central America again in small numbers from frog farms. Because of this, pumilio have seen a huge increase in numbers in the dart frog community and is regularly available.
Common color morphs in captivity
The blue jeans morph of O. pumilio is most common throughout the species range, but is relatively rare in the United States pet trade. Most of these animals came from the original imports during the 1990s, or are descendant from these animals. This morph can be found throughout Costa Rica, as well as mainland Panama.
The Bastimentos color morph of Dendrobates pumilio or "Bastis" typically comes in three morphs, being either red, yellow, or white, with black spots on the back and legs. They are all found together on Isla Bastimentos in Panama, and have been reported to be true breeding to a certain degree, despite the ease of mixing with other varieties. Bastimentos' have recently been arriving in the United States as imports from frog farms.
Chiriqui Grande/Chiriqui River
The rare Chiriqui morph is another frog that has seen recent importation to the United States. This frog is typically green in coloration, with some exhibiting a red coloration. Sometimes, these frogs have blue-green legs and yellow bellies. The Chiriqui River/Grande frogs closely resemble the Cayo de Aqua and Pope Island morphs, but are reported to be collected near either Chiriqui River or Chiriqui Grande. At this time, it is difficult to determine which name is more correct since locality data is unavailable, and they are sometimes incorrectly referred to only as 'Chiriqui'.
Man Creek pumilio is another frog that has seen recent importation into pet stores. They look very similar to the blue jeans morph and are often confused. Both frogs are usually red with blue legs. However, Man Creeks typically have gray legs and arms, and it is not uncommon for them to lack gray entirely on the front limbs. Some Man Creeks do exhibit bluish arms and legs, however, they're typically easy to distinguish by a trained eye.
Man Creeks are often referred to as "Almirante," as they closely resemble the Almirante morph. However, some reports place their collection locale closer to the Man Creek area, and this name is considered more correct at this time. Unfortunately, due to the methods of collection by the frog farms, locality data is missing on this morph, resulting in a great deal of confusion and frustration within the hobby world.
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